250 i6 running a bit rough?

Discussion in 'Technical' started by RathEmpire, Apr 6, 2017.

  1. RathEmpire

    RathEmpire Member

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    hey guys, sorry to bug you again, but now that i've got the choke working right, and the idle's set where I want them (1200 for fast idle, 650-750 for curb idle) it's still running a tad rough, hopefully this video displays it well enough.



    what do you think would be causing this? Wrong setting on the idle air mix screw? Timing a bit off?

    I have the pertronix ignition so it's not a points issue. I double checked the gap for the pertronix module as well and it's bang on.


    Yes I know the muffler is ghetto, it's the one off my truck. I'm just using it on there when I work on the car in the driveway so the neighbors don't get too upset.
     
    Last edited: Apr 6, 2017
  2. Krazy Comet

    Krazy Comet Tom

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    That's cylinders dropping out intermittently, usually a ignition issue(spark plugs, maybe wires/dist cap) but can be caused by lean idle mixture... Adjusting the mixture may help... It may just need a old fashioned Italian tune up, take it out for a good hard run...
     
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  3. RathEmpire

    RathEmpire Member

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    alright i'll tinker with the idle mix screw. The plugs, wires are all brand new and I checked the plug gaps before installing.

    any suggestion on where to start on the idle mix? I've heard two different things, 1.5 turns out from seated, and 3 turns out from seated. Where should I start?I think it's around 1.5 right now. so turning it out more will richen it correct?
     
  4. Krazy Comet

    Krazy Comet Tom

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    The v8 carbs are generally 1.5 turns out but I believe most 6cyl carbs are two to three...

    Really makes no difference, use a vacuum gage and adj for smoothest idle & highest vacuum, if necessary correct idle speed with it's adjustment...
     
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  5. RathEmpire

    RathEmpire Member

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    okay cool. I'll start at 3 then, and hook the vacuum gauge up and adjust from there.
     
  6. Krazy Comet

    Krazy Comet Tom

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    Start from where it is now... Turn it inward and if it stumbles start turning it out...
     

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